Section 22 exempts a person from criminal responsibility where, at the time of doing the act, that person, by reason of unsoundness of mind, was incapable of knowing either the nature of the act, or that what he was doing was wrong or contrary to law.
Verified against the National Crime Records Bureau's official BNS–IPC concordance (Sankalan Portal) and cross-checked directly against the bare text of both Acts. Section 22 is marked Exact correspondence:
| BNS 22 | Covers | IPC, 1860 equivalent | Category |
|---|---|---|---|
| 22 | Act of a person of unsound mind | S.84 (word-for-word identical rule) | Exact |
Comparing the bare text directly, BNS Section 22 reproduces old IPC Section 84 without any change whatsoever, down to the exact wording. This is the codified version of what is commonly known internationally as the M'Naghten rule for legal insanity.
Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, is incapable of knowing the nature of the act, or that he is doing what is either wrong or contrary to law.
Source: Bharatiya Nyaya Sanhita, 2023 (Act No. 45 of 2023), as published in the Gazette of India Extraordinary.
This section provides the legal test for what is commonly called the insanity defence, and it is narrower than the everyday or medical understanding of mental illness. Unsoundness of mind, on its own, is not enough; the section requires that, at the time of the act, the unsoundness of mind actually rendered the person incapable of one of two specific things — either knowing the nature of the act itself (for instance, not understanding that a knife thrust would kill, rather than believing it was some other, harmless act), or knowing that the act was wrong or contrary to law (understanding what was physically being done, but being incapable, due to the mental condition, of appreciating that it was wrong). A person who suffers from a genuine mental illness but who nonetheless understood what they were doing and knew it was wrong does not qualify for this exemption, however serious the underlying condition. The focus throughout is on the person's cognitive capacity at the precise time of the act, not on a diagnosis in the abstract or the person's mental state before or after.
These judgment(s) relate to Section 22 as a whole rather than to one specific sub-section, and so are presented together here rather than alongside a particular clause above.
The accused, who had a documented history of acute psychotic disorder, attacked and killed his grandfather with a sharp-edged weapon. The trial court acquitted him on the ground of insanity; the High Court reversed that acquittal and convicted him. The Supreme Court restored the acquittal, holding that what Section 22 (old IPC Section 84) requires is legal insanity — an incapacity, at the time of the act, to know the nature of the act or that it was wrong or contrary to law — not merely a medically diagnosed psychiatric condition. The Court also reaffirmed that the accused's burden in raising this defence is only to the civil standard of preponderance of probabilities, not proof beyond reasonable doubt, and that even a partial, reasonable-doubt-raising showing can be enough if it undermines the prosecution's own proof of mens rea.
Currency check: decided September 2023, applying long-settled Supreme Court authority (Dahyabhai Chhaganbhai Thakker v. State of Gujarat and later cases) on the legal-versus-medical-insanity distinction and the burden of proof; no overruling found in this review.
No. The mental condition must have actually rendered the person, at the time of the act, incapable of knowing the nature of the act or that it was wrong or contrary to law. A diagnosed condition that did not affect this specific capacity does not qualify.
Specifically at the time of doing the act. The focus is the person's cognitive capacity at that precise moment, not a general diagnosis or the person's condition before or after.
The act is not an offence at all, though separate procedural consequences under the Bharatiya Nagarik Suraksha Sanhita, such as safe custody or treatment, typically follow a finding under this section, rather than an ordinary, unconditional acquittal.